RBP4 and hypertensive disorder: Furthermore, mechanistic interactions of antihypertensive pharmaceutical agents could be involved as, for example, serum vitamin A has recently been suggested to modify the association of β-blockers with all-cause mortality in individuals with suspected coronary heart disease.61 Experimental studies are warranted to elucidate the biological processes that underly the heterogenous cardiometabolic risk relation of circulating retinol and RBP4 levels across hypertension strata.